In computer based process control systems, e.g., for controlling manufacturing and process industries, such as chemical plants, oil refineries, pulp and paper mills, steel mills, etc., there is typically a need for monitoring a wide range of control objects. In particular this monitoring typically includes an operator visually examining a user interface, typically presented on one or more computer screens, to identify potential problems with the process control system. It may be difficult for the operator to in an efficient manner acquire continuous feedback of the status of the control objects of the process control system.
In process control systems sound is often used when there is an event or alarm the operator need to acknowledge. That is, sound effects are used to indicate events that have occurred or something else that needs the operator's attention. For example, when an alarm is sounded, the operator may have to look at one or more screens to detect what control object in the process control system the alarm corresponds to.
Operators in control rooms typically spend most of their time at operator workstations. However, they may also perform work away from the workstations. For example, they may lookup blueprint schematics, help a colleague at a different workstation, or go for a cup of coffee in a lunch room. Even though operators are expected to be found at their operator workstations, they can move around.
Operator control rooms often have several operator workstations. To reduce noise level and interference between operator workstations, a known solution is to equip operator workstations with sound showers. A sound shower is a super directed speaker that only an operator sitting or standing at the workstation is able to hear. This reduces the noise level in the control rooms. However, if an operator is not present at his workstation, there is a risk that he will miss a notification that is delivered via the sound shower.
Systems are known where operators are able to manually switch between the sound shower and regular speakers of a control room in order to control where in the control room notifications can be heard. However there is room for improvement of prior art solutions with respect to security in distributing audible notifications to operators.